What certification is required for a second in command under 14 CFR 121?

The requirement for a second-in-command (SIC) under 14 CFR Part 121 specifies that the individual must hold an Airline Transport Pilot (ATP) certificate that is specific to the aircraft type they will be flying. This regulation is designed to ensure that the SIC is appropriately qualified and has met the rigorous training and experience standards necessary for operating large transport-category aircraft safely.

An ATP certificate indicates comprehensive knowledge and practical experience, which is critical when operating an aircraft in commercial aviation settings. The additional requirement of having a type rating for the specific aircraft aligns with safety and operational integrity, further assuring that the SIC can handle the unique systems and performance characteristics of that aircraft.

While other certifications, such as a private or commercial pilot certificate, may allow for various types of flying, they do not meet the regulatory standards set forth for the SIC in the specific context of 14 CFR Part 121 operations. Hence, the option of an Airline Transport Pilot certificate with a type rating appropriately fulfills the necessary qualifications.